“He said he was doing about 60,” one source said Saturday of the traumatized driver, Andrew Gramm.

“He said he was going fast and planning to make a U-turn” so that he could spin out at the end of the dead end, the source said.

Gramm, 20, blew past two signs reading “Dead End,” and then barreled through the windswept rain down the dark block where 19th Avenue meets the creek’s embankment.

But as he tried to make his ­U-turn, the car struck the curb and he lost control, sources said.

The car then either skidded on its side into the creek, or went airborne directly into the water, sources said.

The car landed upside down, sinking immediately. Unable to escape, the victims drowned in water only 8 feet deep.

A metal guardrail that used to protect that spot apparently collapsed long ago, and lies there covered with rust and vines.

“That section hasn’t been barricaded in 10 years,” said a worker, Julio, at Deborah NYC, a car-and-limo service with an office just 300 yards from the site.

Officials are looking into why the guardrail was down, a city Department of Transportation spokesman said.

Meanwhile, city workers moved a massive concrete barricade to the spot to secure it.

Gramm was the only person in the car with his window down, one source said. He was able to climb out, clamber up the embankment and run to flag down help from a passing car.

He had no alcohol in his system and did not appear to have been high, investigators said.

The bodies of his pals — college students who live within a five-minute walk of each other in East Elmhurst, Queens — were pulled one by one from the creek, a 1,000-foot-long East River inlet that got its name from the nearby Steinway & Sons piano factory.

“If he hadn’t got out of the car, no one would have known it was in the water,” at least until the tide went down Saturday, one investigator said.

Dead are Darius Fletcher, a 21-year-old communications student at William Patterson University; Jaleel Furtado, 20, a student at St. Peter’s College; Jada Butts, 19, a second-year student at Borough of Manhattan Community College; and Crystal Gravely, 19, also of BMCC.

They were all good kids, close friends and motivated students, according to pals and neighbors.

Gravely, who was putting herself through school working as a receptionist at Jakari J hair salon on 99th Street, would have turned 20 Saturday.

“Oh my God!” her distraught ­father, Ronnie, cried as he sat rocking back and forth on the stoop of his home on 96th Street Saturday morning. Tears ran down his cheeks.

“That’s their only child,” said neighbor Margaret Henderson, 58, of the dad and mom, known in the neighborhood as Tiny. “Her father was always talking about her getting excellent grades in school,” added Henderson, a customer-service representative.

“They were good kids,” she said of the friends. “They don’t drink. They weren’t your pants-sagging kids . . . These were young people who had their whole lives ahead of them.”

At a poignant memorial service Saturday night at PS 127 in East Elmhurst, mourners sang Happy Birthday to Gravely.

“Our days will never be the same. We lost a daughter, a niece, a neighbor,” said Rev. Vinnie Green, 46, of the family’s Friendship Church of Christ Baptist.

The quintet had met at Fletcher’s house on 98th Street before heading out to celebrate Gravely’s birthday with a dinner at a nearby Buffalo Wild Wings. They went into the water at around 10:30 p.m.

“Those are his friends,” said Steve Owens, 46, a ­barber who used to cut Furtado’s hair, referring to Gramm’s speeding.

“He has to live with the loss,” said Owens, of Marion’s Beauty Salon. “I can’t imagine what he is going through right now.”